1. Technical Field
The present disclosure generally provides compositions and methods for treating B-cell disorders and, more specifically, a humanized anti-CD37 small modular immunopharmaceutical (SMIP) molecule, as well as synergistic combination therapies of CD37-specific binding molecules with bifunctional chemotherapeutics for use in treating or preventing B-cell related autoimmune, inflammatory, or hyperproliferative diseases.
2. Description of the Related Art
The human immune system generally protects the body from invading foreign substances and pathogens. One component of the immune system is B lymphocytes, also referred to as B-cells, which produce antibodies that protect the body by binding to, and in some cases mediating destruction of, a foreign substance or pathogen. In some instances, however, the immune system functions can go awry and disease results. For example, there are numerous cancers, autoimmune diseases, and inflammatory diseases that involve uncontrolled proliferation of B-cells.
B-cells can be identified by molecules on their cell surface, such as CD37. CD37 is a heavily glycosylated 40-52 kDa protein that belongs to the tetraspanin transmembrane family of cell surface antigens, which is highly expressed on normal antibody-producing B-cells but not on pre-B-cells or plasma cells. In addition to normal B-cells, almost all malignancies of B-cell origin are positive for CD37 expression, including chronic lymphocytic leukemia (CLL), non-Hodgkins lymphoma (NHL), and hairy cell leukemia (Moore et al., J. Pathol. 152:13 (1987); Merson and Brochier, Immunol. Lett. 19:269 (1988); and Faure et al., Am. J. Dermatopathol. 12:122 (1990)).
A few CD37 specific immunotherapies have been developed. An IgG1 murine monoclonal antibody specific for CD37, MB-1, was labeled with 131I and tested in a clinical trial in the treatment of NHL (see Press et al., J. Clin. Oncol. 7:1027 (1989); Bernstein et al., Cancer Res. (Suppl.) 50:1017 (1990); Press et al., Front. Radiat. Ther. Oncol. 24:204 (1990); Press et al., Adv. Exp. Med. Biol. 303:91 (1991) and Brown et al., Nucl. Med. Biol. 24:657 (1997)). The MB-1 antibody lacks Fc effector functions, such as antibody-dependent cellular cytotoxicity (ADCC), and the naked MB-1 antibody did not inhibit tumor growth in an in vivo xenograft model (Buchsbaum et al., Cancer Res. 52:6476 (1992)). In addition, an immunoconjugate having adriamycin linked to G28-1, another murine monoclonal anti-CD37, was administered to mice and shown to be internalized with adriamycin being released intracellularly (see, Braslawsky et al., Cancer Immunol. Immunother. 33:367 (1991)). An engineered fusion protein, termed a small modular immunopharmaceutical (SMIP™) product, directed to CD37 is currently being tested in humans (see, e.g., US Patent Application Publications 2003/0133939 and 2007/0059306).
Although there has been extensive research carried out on antibody-based therapies, there remains a need in the art for alternative or improved compositions and methods for treating B-cell associated disorders or diseases.